1. Field of the Invention
The present invention relates to a backside illuminated semiconductor light-receiving device, an optical receiver module which incorporates the backside illuminated semiconductor light-receiving device therein, and an optical transceiver which incorporates the backside illuminated semiconductor light-receiving device therein.
2. Description of the Related Art
The backside illuminated semiconductor light-receiving device is a photoelectric conversion element which includes a semiconductor substrate and a light receiving part which is formed on a front surface of the semiconductor substrate, and receives light incident from a back surface of the semiconductor substrate by the light receiving part.
In general, a backside illuminated semiconductor light-receiving device is, for facilitating the reception of light incident from a back surface of a semiconductor substrate, mounted on a ceramic-made carrier, for example, in an up-side-down manner such that the back surface faces upward and a front surface faces downward. To be more specific, an electrode of a first conductive type (for example, a P-type electrode) and an electrode of a second conductive type (for example, an N-type electrode) are connected to two electrodes formed on the front surface of the carrier respectively by soldering. Here, the electrode of the first conductive type is made conductive with one side of a PN junction portion which is formed on an upper surface of a light receiving mesa portion, and the electrode of the second conductive type is pulled out to an upper surface of a mesa portion and is made conductive with the other side of the PN junction portion which is formed in a region on a front surface of the substrate different from a region where the light receiving mesa portion.
However, usually, an upper surface of the light receiving mesa portion on which the electrode of a first conductive type is formed has a narrower area compared to an upper surface of a pedestal on which the pull-out electrode of a second conductive type is formed and hence, there exists a possibility that the light receiving mesa portion is broken due to a pressure concentrating on the upper surface side of the light receiving mesa portion.
To cope with such a drawback, JP 2000-349113 A discloses a semiconductor light-receiving device having the structure where on a side opposite to a mesa portion on which an electrode of a second conductive type is formed, a mesa portion having the same shape as the former mesa portion is formed with a light receiving mesa portion (operation region) sandwiched between the mesa portions. Due to such structure, a pressure applied to the upper surface of the light receiving mesa portion when the semiconductor light-receiving device is mounted on a printed circuit board or the like by thermo compression bonding can be reduced whereby breaking of the light receiving mesa portion or the insufficient adhesion of the device can be prevented.